Lens module

ABSTRACT

A lens module with an optical axis passing therethrough from an object side to an image side includes a lens housing and two lenses disposed in the lens housing. The first lens has a first refract portion and a first positioning portion encircling the first refract portion. A first jointing structure is formed on the image side surface of the first positioning portion and molded with the first refract portion as a single integral. The second lens has a second refract portion and a second positioning portion encircling the second refract portion. A second jointing structure is formed on the object side surface of the second positioning portion and molded with the second refract portion as a single integral. The jointing structures are engaged to align the lenses along the optical axis, and the refract portions are coaxial with each other and have the axis as the optical axis.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a lens module, and more particularly to a lensmodule used in mobile electronic products.

2. The Related Art

With the popularity of camera phones, the quality of photography hasbecome one of the main considerations for consumers to purchase a newmobile phone having a lens module therein. In order to make photographicquality of the lens module better and the size and the weight of themobile phone slimmer, the allowable error value of assembling opticallens of the lens module is also getting strict. Take a generaltwo-megapixel camera lens for an example, the eccentric error whileassembling the optical lenses must be less than 3 μm.

Referring to FIG. 1, a conventional lens module includes a lens housing90 and several optical lenses 91 mounted in the lens housing 90. Each ofthe optical lenses 91 includes a refract portion 92 closed to theoptical axis 94 and a positioning portion 93 away from the optical axis94. The optical lens 91 is assembled and fixed in the lens housing 90 bymeans of the positioning portion 93. So the manufacturing error of thelens housing 90 will affect the assembling error of the optical lens 91.Therefore, in order to reduce the assembling error of the optical lens91, the manufacturing error of the lens housing 90 must be controlled ina sufficiently small value. However, since the manufacture process andthe mold precision of the optical lens 91 are different from that of thelens housing 90, the lens housing 90 often has a higher manufacturingtolerance than the optical lens 91. It causes a higher assembling errorof the lens module and a lower production yield.

In view of these disadvantages above, the structure of the conventionallens module needs to be improved.

SUMMARY OF THE INVENTION

An objective of this invention is to provide a lens module with highassembling accuracy and high production yield. An optical axis passesthrough the lens module from an object side to an image side. The lensmodule includes a lens housing, a first lens and a second lens which aredisposed in the lens housing from the object side to the image side insequence.

The first lens has a first refract portion through which the opticalaxis passes and a first positioning portion away from the optical axisand encircling the first refract portion. A first jointing structure isannularly formed on the image side surface of the first positioningportion and molded with the first refract portion as a single integral.The second lens has a second refract portion through which the opticalaxis passes and a second positioning portion away from the optical axisand encircling the second refract portion. A second jointing structureis annularly formed on the object side surface of the second positioningportion and molded with the second refract portion as a single integral.The first jointing structure and the second jointing structure areengaged with each other to align the first lens and the second lensalong the optical axis, and the first refract portion of the first lensand the second refract portion of the second lens are coaxial with eachother and have the axis as the optical axis.

As described above, each of the positioning portions and the jointingstructures in this invention are molded with the refract portions as asingle integral, so the positioning portion and the jointing structurehave less manufacturing tolerance. Therefore, the lenses are capable tobe assembled with high assembling accuracy together so that avoidsrelative positioning deviation of the lens caused by the manufacturingerror of the lens housing, and improves the production yield of the lensmodule.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be apparent to those skilled in the art byreading the following description, with reference to the attacheddrawings, in which:

FIG. 1 shows a cross-sectional view of a conventional lens module;

FIG. 2 shows a cross-sectional view of a lens module in this invention;

FIG. 3 shows a cross-sectional view of the lens module of FIG. 2,wherein a first lens and a second lens are not yet jointed; and

FIG. 4 is a cross-sectional view showing the jointing process of thefirst lens and the second lens of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 2, a lens module in accordance with the presentinvention is shown and an optical axis 13 passes through the lens modulefrom an object side 11 to an image side 12. The lens module includes alens housing 10 and three lenses which are disposed in the lens housing10 from the object side 11 to the image side 12 in sequence, wherein thethree lenses are designated as a first lens 20, a second lens 30 and athird lens 40 respectively.

The first lens 20 has a first refract portion 21 through which theoptical axis 13 passes and a first positioning portion 22 away from theoptical axis 13 and encircling the first refract portion 21. The firstlens 20 is arranged and fixed to the lens housing 10 by means of thefirst positioning portion 22. A first jointing structure 23 is annularlyformed on the image side surface of the first positioning portion 22.The first jointing structure 23 is molded with the first refract portion21 as a single integral, so the first jointing structure 23 has the samegreat manufacturing precision as producing optical-component, and hasvery low manufacturing error.

The second lens 30 has a second refract portion 31 through which theoptical axis 13 passes and a second positioning portion 32 away from theoptical axis 13 and encircling the second refract portion 31. A secondjointing structure 33 is annularly formed on the object side surface ofthe second positioning portion 32, and also molded with the secondrefract portion 31 as a single integral, so the second jointingstructure 33 also has the same great manufacturing precision asproducing optical-component, and has very low manufacturing error. Thefirst jointing structure 23 and the second jointing structure 33 areengaged with each other to align the first lens 20 and the second lens30 along the optical axis 13. The first refract portion 21 of the firstlens 20 and the second refract portion 31 of the second lens 30 arecoaxial with each other and have the axis as the optical axis 13.

Since the first lens 20 and the second lens 30 are positioned byengaging the first jointing structure 23 with the second jointingstructure 33, so the manufacturing error of the lens housing 10 will notaffect the eccentric error between the first lens 20 and the second lens30. Moreover, the jointing structures 23, 33 are respectively moldedwith the refract portions 21, 31 as a single integral by optical moldsthat are used for casting optical lenses, so the manufacturing error ofthe jointing structure 23, 33 is very small, and it effectively reducesthe eccentric error between the first lens 20 and second lens 30.

In this embodiment, the total quantity of lenses are three. A thirdjointing structure 38 is formed on the image side surface of the secondlens 30, and a fourth jointing structure 41 is formed on the object sidesurface of the third lens 40. The third lens 40 is fixed with the secondlens 30 by jointing the fourth jointing structure 41 with the thirdjointing structure 38. The third jointing structure 38 and the fourthjointing structure 41 are also molded with optical mold that is used forcasting optical lenses, so the manufacturing error can also beminimized. But in use, the quantity of lenses is adjustable according tothe requirement, and should not be limited to three.

Referring to FIG. 3 and FIG. 4, in this embodiment, the first jointingstructure 23 is an annular rib protruding towards the second lens 30 onthe image side surface of the first positioning portion 22. The annularrib has a resisting face 24 vertical to the optical axis 13 and an outersidewall 25 parallel to the optical axis 13. The corner defined by theouter sidewall 25 and the first positioning portion 22 defines a guidingslope 26 with the slope face thereof connecting with the outer sidewall25 and the image side surface of the first positioning portion 22. Thesecond jointing structure 33 is an annular groove recessed into theobject side surface of the second positioning portion 32 and facing tothe annular rib. The annular groove has a stopping face 34 vertical tothe optical axis 13 and an inner wall 35 parallel to the optical axis13. A guiding face 36 is slantwise connected between the inner wall 35and the object side surface of the second positioning portion 32.

When the second jointing structure 33 joints with the first jointingstructure 23, the guiding slope 26 and the guiding face 36 cooperatewith each other to guide the second lens 30 to align with the first lens20 automatically along the optical axis 13. When the first jointingstructure 23 is completely jointed with the second jointing structure33, the first refract portion 21 of the first lens 20 and the secondrefract portion 31 of the second lens 30 are coaxial with each other andhave the axis as the optical axis 13. The outer sidewall 25 abutsagainst the inner wall 35 to keep the first lens 20 and the second lens30 coaxial, and the resisting face 24 resists against the stopping face34 to keep the distance between the first lens 20 and the second lens 30constant.

As described above, each of the positioning portions 22, 32 and thejointing structures 23, 33 are molded with the refract portions 21, 31integrally, so the positioning portions 22, 32 and the jointingstructures 23, 33 are manufactured in high manufacturing precision.Therefore, the lenses 20, 30 are capable to be assembled with highassembling accuracy together so that avoids relative positioningdeviation of the lenses 20, 30 caused by the manufacturing error of thelens housing 10, and improves the production yield of the lens module.

What is claimed is:
 1. A lens module with an optical axis passingtherethrough from an object side to an image side, comprising: a firstlens having a first refract portion through which the optical axispasses and a first positioning portion away from the optical axis andencircling the first refract portion, a first jointing structure beingannularly formed on the image side surface of the first positioningportion and molded with the first refract portion as a single integral;a second lens having a second refract portion through which the opticalaxis passes and a second positioning portion away from the optical axisand encircling the second refract portion, a second jointing structurebeing annularly formed on the object side surface of the secondpositioning portion and molded with the second refract portion as asingle integral; and a lens housing in which the first lens and thesecond lens are disposed from the object side to the image side insequence, wherein the first jointing structure and the second jointingstructure are engaged with each other to align the first lens and thesecond lens along the optical axis, the first refract portion of thefirst lens and the second refract portion of the second lens are coaxialwith each other and have the axis as the optical axis.
 2. The lensmodule as claimed in claim 1, wherein the first jointing structure is anannular rib protruding towards the second lens on the image side surfaceof the first positioning portion, the annular rib has a resisting facevertical to the optical axis and an outer sidewall parallel to theoptical axis, and the second jointing structure is an annular grooverecessed into the object side surface of the second positioning portionand facing to the annular rib, the annular groove has a stopping facevertical to the optical axis and an inner wall parallel to the opticalaxis, when the first jointing structure is engaged with the secondjointing structure, the outer sidewall abuts against the inner wall tokeep the first lens and the second lens coaxial, and the resisting faceresists against the stopping face to keep the distance between the firstlens and the second lens constant.
 3. The lens module as claimed inclaim 2, wherein the corner defined by the outer sidewall and the firstpositioning portion defines a guiding slope with the slope face thereofconnecting with the outer sidewall and the image side surface of thefirst positioning portion, and a guiding face is slantwise connectedbetween the inner wall and the object side surface of the secondpositioning portion, when the second jointing structure is engaged withthe first jointing structure, the guiding slope and the guiding facecooperate with each other to guide the second lens to align with thefirst lens automatically.
 4. A lens module with an optical axis passingtherethrough from an object side to an image side, comprising: a firstlens having a first refract portion and a first jointing structure whichis annularly formed on the image side surface around the first refractportion; a second lens having a second refract portion and a secondjointing structure which is annularly formed on the object side surfacearound the second refract portion; and a lens housing in which the firstlens and the second lens are disposed from the object side to the imageside in sequence, wherein the first jointing structure and the secondjointing structure are engaged with each other to align the first lensand the second lens along the optical axis, the first refract portion ofthe first lens and the second refract portion of the second lens arecoaxial with each other and have the axis as the optical axis.
 5. Thelens module as claimed in claim 4, wherein the first jointing structureis an annular rib protruding towards the second lens on the image sidesurface, the annular rib has a resisting face vertical to the opticalaxis and an outer sidewall parallel to the optical axis, and the secondjointing structure is an annular groove recessed into the object sidesurface and facing to the annular rib, the annular groove has a stoppingface vertical to the optical axis and an inner wall parallel to theoptical axis, when the first jointing structure is engaged with thesecond jointing structure, the outer sidewall abuts against the innerwall to keep the first lens and the second lens coaxial, and theresisting face resists against the stopping face to keep the distancebetween the first lens and the second lens constant.
 6. The lens moduleas claimed in claim 5, wherein the corner defined by the outer sidewalland the image side surface of the first lens defines a guiding slopewith the slope face thereof connecting with the outer sidewall and theimage side surface, and a guiding face is slantwise connected betweenthe inner wall and the object side surface of the second positioningportion, when the second jointing structure is engaged with the firstjointing structure, the guiding slope and the guiding face cooperatewith each other to guide the second lens to align with the first lens.